Acetyl L-Carnitine

The supplement that burns fat and powers the brain.

Acetyl-L-carnitine is an amino acid naturally produced in your body to generate energy. It’s also found in animal protein — namely, red meats. Many people supplement with acetyl-L-carnitine, because of its potential benefits

  • You can use ALCAR to enhance your mitochondrial function, cognition, workouts, and more. ALCAR helps your mitochondria (the powerhouses of your cells) burn fat and create more energy — especially for your muscles and brain
  • ALCAR also helps your muscle mitochondria burn fat, which can increase your endurance, give you an edge in the gym, and help you recover faster.

Here’s a closer look at how ALCAR works

Acetyl-L-carnitine and weight loss: how it helps burn fat

When you take ALCAR, it turns into carnitine in your body, and if your insulin levels are low — for example, from eating a keto diet (like the Bulletproof Diet), doing intermittent fasting, working out intensely, or being in a calorie deficit — carnitine becomes very important for burning fat.

​When your insulin is low, your mitochondria start turning to fat for fuel.[1] They grab onto stored body fat (or fat you eat), break it down into fatty acids, and send the fatty acids to your mitochondria. Your mitochondria turn those fatty acids into ATP (energy) that powers your cells.

​But fatty acids can’t get into your mitochondria alone. They use something called a carnitine shuttle. Basically, carnitine latches onto fatty acids and carries them into your mitochondria. It gives your mitochondria the raw materials to produce lots of energy and function at their best.

​In other words, you need carnitine to metabolize fat. If you’re low on carnitine, fat can’t get into your mitochondria, and you struggle to use it for fuel.[2] But with abundant carnitine, your fat metabolism works like a well-oiled machine. That’s where ALCAR supplements come in, and why they’re so popular with bodybuilders.

Acetyl-L-carnitine for mood, memory and cognitive decline

Acetyl-L-carnitine is a supplement form of L-carnitine that can pass your blood-brain barrier, giving it access to the dense collection of mitochondria in your brain, as well as to the mitochondria in the rest of your body. That explains why ALCAR is becoming so popular as a nootropic supplement (something that makes your brain work better).

Here’s what the research has to say about using ALCAR to make your brain work better

  • More mental & physical energy: Older men and women who took ALCAR daily saw a significant boost to their physical and mental energy levels, as well as better overall cognitive ability
  • Improves cognitive function: People with low carnitine levels see a major decrease in brain function. Taking ALCAR improves that brain function. A lot. In a recent study, 8 out of 14 participants reversed a diagnosis of dementia and returned to their full cognitive abilities after taking ALCAR daily
  • Lowers inflammation: Acetyl-L-carnitine decreases inflammation in healthy adults. Part of it is because ALCAR increases glutathione, your body’s master antioxidant.[5] Side note: glutathione is awesome for hacking hangovers. And, as it turns out, ALCAR decreases damage to brain cells after drinking, too
  • Boosts circulation: In healthy adults, ALCAR increased circulation and nutrient-rich blood flow after a high-fat meal. Good blood flow is an essential part of muscle and brain function.
  • Improves focus: Acetyl-L-carnitine improves attention, both in kids with ADHD[8] and adults who struggle with mental fatigue

Who should use acetyl-L-carnitine as a nootropic

It’s worth mentioning that, although a few of these studies are in healthy young adults, a lot of acetyl-L-carnitine research is in older people. It’s clear that ALCAR is great for anti-aging, but what if you’re young and thriving, and want an extra edge?

As is the case with many nootropics, ALCAR is popular in the brain-hacking world thanks to lots of individual reports about how much it helps cognition. This is one of those supplements that’s worth trying on your own, to see if you notice any benefit

What about ALCAR for improving your workouts?

  • Acetyl-L-carnitine for exercise and recovery
  • Increases strength: Resistance-trained young men who took carnitine 90 minutes before intense exercise enjoyed a significant increase in power output, as well as lower lactate levels (lactate contributes to the burning feeling in your muscles)
  • Burns more fat: Young men who took carnitine burned more fat during moderate exercise, and their muscles produced more energy during intense exercise
  • Boosts testosterone: Men who took acetyl-L-carnitine after lifting had more dense hormone receptors in their muscles, which may have improved their testosterone uptake. In other words, ALCAR doesn’t increase your testosterone; it makes you better at using the testosterone you have (Here’s how to increase your testosterone).
  • Speeds recovery: ALCAR can speed up recovery and decrease muscle inflammation after exercise, in both men and women
  • Better insulin sensitivity: ALCAR improves insulin sensitivity in people who don’t process glucose well
  • Builds muscle: ALCAR is a powerful anti-aging supplement if you’re older and want to build muscle. In older people, it decreases muscle fatigue and increases fat loss
  • Reduces muscle fatigue: One study found that acetyl-L-carnitine decreases muscle fatigue in young people, too

Summing up

Acetyl-L-carnitine and weight loss: how it helps burn fat

ALCAR can help you work harder in the gym and recover faster. And if you’re older, acetyl-L-carnitine is especially useful for maintaining your energy levels and shedding body fat.

​How much acetyl-L-carnitine should you take?
Acetyl-L-carnitine is a valuable addition to your daily supplement routine, especially if you’re an athlete or you’re looking for anti-aging benefits. As with most supplements, timing matters. Here’s what you need to know.

​Most of the studies you just read about used between 1-3 grams of L-carnitine, taken every day. One gram a day seems to be a good place to start. From there, you can increase or decrease the dose as you see fit. Here are sample plans for taking ALCAR:

​Acetyl-L-carnitine for nootropic benefits/anti-aging:
2g/day; half first thing in the morning, half in the afternoon

​Acetyl-L-carnitine for fitness and fat-burning:
2-3g day; half 90 minutes before exercise (to increase your muscle endurance), half after exercise (to speed up recovery)


While ALCAR is generally considered safe for most people, you could experience some side effects, including upset stomach, nausea, vomiting, headache, dry mouth, and restlessness.

  • Consult your physician before starting any new supplement, especially if you’re pregnant, breastfeeding, or have a serious medical condition
  • Acetyl L - carnitine may interfere with thyroid function and is best avoided if you have an underactive thyroid.
  • People with a history of seizures may also want to steer clear of ALCAR
  • Do not use acetyl-L-carnitine if you’re taking blood-thinning medication.
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